1. Field of the Invention
The present invention relates generally to data entry and manipulation devices for computers, and more particularly, to a system for a tracking body movements in a virtual reality system and for integrating data generated by the device into a virtual reality system in a real time environment.
2. Description of Related Art
Virtual reality systems are computer based systems that provide experiences to a participant acting in a simulated environment that forms a three dimensional virtual world. These systems are used in several different applications such as commercial flight simulators, entertainment systems, computer games and video arcade games to name a few.
In virtual reality systems, the participant typically wears a head-mounted device that enables viewing of a virtual reality world generated by the computer. The system also includes an interaction means, such as a pointing device or specially configured glove containing sensors and actuators, for interacting with objects in the virtual world. In somewhat sophisticated systems, a data generating body suit, containing sensors and actuators, may be provided so that the user can influence and has a realistic feel of objects in the virtual world.
Computer generated animation is an increasingly prevalent media form. Computer generated animation is currently being used in such applications as full-length motion pictures, crime reenactments, short length films, television commercials, and children's cartoons. However, a disadvantage of known computer generated animation, is that the animation is programmed into the computer to form a cartoon or other animation, similar to a draftsman drawing cells in a cartoon strip, prior to the animation being run for display. It is not possible for a user to interact with the computer animation while the animation is being shown, such as controlling the movement of characters or objects. It would be advantageous to provide a system for interacting with computer generated animation in "real time", i.e., while the animation is running on a computer where the participant can control objects in the animation.
One means for controlling an object, such as the body movements of a selected character or characters in real time computer generated animation, would be to provide a data input means or a data generating body suit which would provide appropriate data to the computer while the animation program is running. The data generated by the suit can be transmitted to a computer for integration into the running animation for altering the animation in real time.
Devices have been provided for use in virtual reality systems that measure relative position and orientation of a body in space, and then transmit relative data to a computer for processing the data. These devices typically include a body suit that has a number of sensors, or receivers. A transmitter sends signals to the receivers for determining position and orientation in space. The signal is received and processed to determine the position and orientation of the body suit. This information is used to control the movements of an object, such as a character, in a virtual reality program. The object behaves in a manner controlled by the body movements of the wearer of the suit, such as the character mimicking the body movements of the wearer.
One such device is disclosed in U.S. Pat. No. 4,945,305, to Blood. The device disclosed therein quantitatively measures the position of receiver antennae relative to transmitter antennae. The device includes transmitter antennae and receiver antennae which detect the DC magnetic vectors generated by the transmitters. A signal processor is provided to ascertain the magnitude of the detected DC magnetic vectors, to quantitatively compute the relative position and orientation of the receiver antennae relative to the transmitter antennae, and to compensate for the effects of the earth's magnetic field on the operation of the device.
U.S. Pat. No. 5,600,330, to Blood, discloses a device for determining position and orientation of receiving antenna with respect to transmitting antenna using electromagnetic fields. The device includes transmitting means for transmitting electromagnetic fields and receiving means for receiving the transmitted electromagnetic fields. The receiving means is disposed inside a volume of space where non-dipole field conditions exits.
U.S. Pat. No. 5,337,758, to Moore et al., is directed to a spine motion analyzer and method. The disclosed spine analyzer includes mechanical linkage attached to a subject below and above the portion of the spine to be monitored. Transducers are connected to the linkage to provide electrical signals that can be processed to provide video, printed, and auditory indications of the spinal movements.
A disadvantage of the above systems is that they are directed to measuring only general body position and orientation. These describe the general location of a wearer of the receiving means relative to the transmitting means, or the wearer bending over or rotating their entire torso relative to the transmitting means. While these devices are capable of measuring significant body movements, they are not well suited for accurately tracking subtle body movements, such as wrist movements or rotation of a foot, for example.
Thus, there exists a need for a system for a tracking body movements, and particularly subtle body movements, in a virtual reality system and for integrating data generated by the device into a virtual reality system in a real time environment.